Added Cpp compatibility for components/spi_flash/include/esp_flash_spi_init.h
Added Cpp compatibility for components/spi_flash/include/esp_flash_spi_init.h

Merges https://github.com/espressif/esp-idf/pull/4260

espressif/esp-idf,espressif/esp-idf,espressif/esp-idf,espressif/esp-idf